The present invention relates to an ink jet printer apparatus and method, and more particularly, to an ink jet printer and method for making a printing plate and a proof of a work such as text and/or an image to be printed by the printing plate.
When printing, a printing plate for a work is typically made, and then one or more proofs of the work are printed using the printing plate to allow determining desirability and accuracy of the printed image before a large number of prints are printed. The proofing activity might take several stages: an initial, creative stage in which a computer display might be adequate for proofing; an intermediate stage in which a desktop-type inkjet or thermal printer output might be used; and a final, more critical stage in which an accurate picture of the final plate result, including the micro-structure of the halftone dots to be produced on the plate, is desired. It is toward this last need for an accurate halftone proofer, matched to a corresponding platemaker, that the present invention is directed.
It is known to use an ink jet printer to make printing plates. Reference in this regard, Fromson et al. U.S. Pat. No. 5,750,314 issued May 12, 1998 which discloses a method for selectively imaging a lithographic printing plate using an ink jet printer. In the Fromson et al. method, a substrate is coated with a first material, which is soluble in a first solvent, whereupon a second material, which strongly adheres to the first material and insoluble in the first solvent, is selectively applied by an ink jet printer. The substrate is then developed in the first solvent to establish the image. However, Fromson et al. does not disclose a method or apparatus for producing a proof of a work to be printed, without first requiring making the printing plate.
Therefore, what is required is a method and apparatus for printing a proof of a work to be printed using a printing plate, which does not require first making the printing plate. What are also required are an inkjet printer apparatus and method for making both an accurate proof of a work to be printed and a printing plate for the work.
An object of the present invention is to provide an ink jet printer and method for printing an accurate proof of a work to be printed using a printing plate without first requiring making the printing plate, and for making the printing plate.
With this object in view, the present invention resides in an ink jet printer adapted for printing a proof of a work to be printed and making or completing a printing plate image wise for printing the work, the printer including a first element including circuitry controllably operable for generating ink drops of a first predetermined volume for printing the proof on a proofing receiver, and a second element including circuitry controllably operable for generating liquid drops of a second predetermined volume for making or completing the printing plate image wise, the second predetermined volume being different from the first predetermined volume.
According to an exemplary embodiment of the present invention, the ink jet printer includes a first print head connected in fluid communication with a source of ink for printing the proof of the work, and a second print head in fluid communication with a source of a liquid for making the printing plate, the print heads being disposed for ejecting drops of the ink and the liquid image wise onto a proofing receiver and a treated plate, respectively, positionable on a platen relatively moveable with respect to the print heads. The first element is connected in electrical communication with the first print head and includes a first clock connected to a signal generator operable for producing a drive signal for driving the print head for generating the ink drops of the first predetermined volume for printing the proof on the proofing receiver. The second element includes a second clock connected to the signal generator and operable in conjunction therewith for driving the second print head for generating the liquid drops for printing the image on the treated plate for making or completing the printing plate. A machine control is connected to the signal generator and is operable for selecting the first print head and the first clock for ejecting the ink drops image wise onto the proofing receiver, which can be a sheet of proofing paper or the like, for creating the proof, or the second print head and the second clock for ejecting the liquid image wise onto the treated plate for making or completing the printing plate.
The treated plate for instance can be a grained, anodized aluminum or polyester plate having a hydrophilic surface and having a known surface treatment to control spreading of ink drops thereon. The liquid deposited on the treated surface for instance can include an oleophilic liquid containing a polymer such as pyridine-containing polymer. Such liquids are preferred as they have a known ability to pick up and deliver printing inks to a blanket roller of a printing press. Such liquids are also known for the durability of the dried spots that are formed.
A feature of the present invention is the provision of an ink jet printer adapted for making or image wise completing a printing plate, and a proof of a work to be printed using the printing plate without first requiring making the printing plate.
Another feature of the invention is the provision of an ink jet printer operable to produce drops having different characteristics for printing corresponding images of a work on different printing receivers.
As an advantage of the present invention, a printing plate and a proof of a work to be printed using the printing plate can be produced using the same apparatus.
As another advantage, an accurate proof of a work to be printed using a printing plate can be produced, thus avoiding cost and time lost producing an undesirable or incorrect printing plate.
According to the invention, the volume characteristics of drops of ink or other liquid produced by an ink jet printer can be varied by altering aspects of the drive signal used for producing the drops, including, but not limited to, the voltage, frequency, and/or wave form of the drive signal.
These and other objects, features an advantages of the present invention will become apparent to those skilled in the art upon a reading of the following detailed description when taken in conjunction with the drawings wherein there are shown and described illustrative embodiments of the invention.